Bienz M, Saari G, Tremml G, Müller J, Züst B, Lawrence P A
Zoological Institute, University of Zürich, Switzerland.
Cell. 1988 May 20;53(4):567-76. doi: 10.1016/0092-8674(88)90573-9.
The homeotic gene Ultrabithorax (Ubx) is expressed in specific parts of Drosophila embryos: in a single metamer in the visceral mesoderm and forming a complex pattern limited to a broad domain in the ectoderm and in the somatic mesoderm. Here we use a linked beta-galactosidase gene to identify cis-acting regulatory sequences. In the visceral mesoderm, correct expression of Ubx depends on localized upstream sequences. In the ectoderm, all galactosidase-positive transformants show the same characteristic pattern. The repeated elements of this basal pattern appear to be a sub-pattern of engrailed (en) expression; they depend on en function as well as on sequences in the Ubx RNA leader. We use a mutant (Haltere-mimic) to show that sequences that normally restrict segmental expression of Ubx in the ectoderm are located downstream from the RNA leader.
同源异型基因超双胸（Ubx）在果蝇胚胎的特定部位表达：在内脏中胚层的单个体节中表达，并在外胚层和体壁中胚层的一个广泛区域形成复杂的表达模式。在这里，我们使用一个与之相连的β-半乳糖苷酶基因来鉴定顺式作用调控序列。在内脏中胚层中，Ubx的正确表达依赖于局部上游序列。在外胚层中，所有半乳糖苷酶阳性转化体都表现出相同的特征模式。这种基本模式的重复元件似乎是engrailed（en）表达的一个子模式；它们依赖于en的功能以及Ubx RNA前导序列中的序列。我们使用一个突变体（平衡棒模拟）来表明，通常在外胚层中限制Ubx节段性表达的序列位于RNA前导序列的下游。
